Systems Analysis and Design 5th Edition Mid-term Solution Li Jing, Rachael lijing@se.cuhk.edu.hk © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 1 What calculations are used in economic feasibility? Return on investment(ROI) 3’ Break-even Point(BEP) 3’ Net present value of money(NPV)/Present Value(PV) 3’ Other calculation method 1’ ROI+BEP+NPV(PV)=10’ Refer to the lecture notes © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 2 What are the four phases of the SDLC and what is the major deliverable from each of the phases? Planning 1’ - system request/feasibility study/project plan 1.5’ Analysis 1’ - system proposal/requirements + use case 1.5’ Design 1’ – (system/program/database) specification/Alternative Matrix 1.5’ Implementation 1’ – (installed) system / documentation + migration plan + support plan 1.5’ Name of the phases are simple. Deliverable may be confuse students. Professor gave the correct answer. phases is composed of steps, which rely on techniques that produce deliverables: specific documents that explain various elements of the system © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 3 What is ROI?(4’) Return on Investment (4’) Or Formula (4’) To evaluate a project’s worth(2’) Total benefits:$182,000 and total cumulative costs:$120,000. What would be the ROI?(6’) (182000-120000)/120000=0.5167 6’ Formula given in (a) or (b) 4’ Calculation result 2’ Refer to the lecture note © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 4 What is the difference between systems prototyping and throwaway prototyping methodologies? a functional system 5’ understanding the user requirements and design considerations more quickly 5’ Answer given by Professor. Based on a thorough understanding of all materials. Do not have to get that level. © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. System Prototyping Evolve into final system 1’ Quick 2’ Dirty 2’ Thorough analysis 2’ Quickly provide a system. Following reaction and comments from the users, the developers reanalyze, redesign and reimplement a second prototype. More stable and reliable system. Well-thought-out analysis; using the design prototype to refine key issues before a system is built. Once the issues are resolved, we throw away design prototype Throwaway Prototyping 2’ Throwaway/refine 1’ © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 4 Throwaway prototyping With unfamiliar technology 2’ Complex system 2’ Reliable system 2’ System prototyping Short time schedule 2’ Schedule visibility 2’ Table in the lecture note comparing different prototyping from various aspects © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 5 What are the main differences between the Waterfall Development and the Rapid Application Development methodologies? RAD emerge in response to the weakness of waterfall With unclear user requirement 2.5’ With unfamiliar technology 2.5’ With short time schedule 2.5’ With schedule visibility 2.5’ Refer to the table in lecture notes. Improvements are made taking these four situations into consideration. © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 6 Explain functional and non-functional requirements and give 2 examples in each case for a bank ATM system. Functional requirements what the software should do 2’/ processes 1’ + information 1’ Example 1: allow users to check their balance Example 2: include real-time balance Non-functional requirements characteristics the system should have 4’/ operational 1’ + performance 1’ + security 1’ + cultural and political requirements 1’ Example 1: finish any user operation in 10 seconds Example 2:include all possible safeguards from viruses Functional: Process oriented and information oriented Nonfunctional: Four orientations Example 2: from malicious destruction, viruses, worms, Trojan horses etc. © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 7 What are the steps for writing a use case? Identify the (major) use cases. 2.5’ Identify the major steps for (within) each use cases. 2.5’ Identify elements within steps 2.5’ Confirm the use case 2.5’ Activities of each steps given is also OK. Refer to the lecture notes © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 8 What are external and temporal event triggers? Give an example each for a bank ATM system. External events occur outside the system, usually triggered by someone who interacts with the system. 3’ Example: event trigged by users when they withdraw some money from an ATM 2’ Temporal events occur at a defined point in time, such as the end of a workday or the end of every month. 3’ Example: a user logs into the ATM system and does nothing for a long time, the ATM will expire current session Get the answer simply from the name. © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 9 What are the characteristics of (a) a project and (b) process? Project(also called temporary effort) Clear start and end dates/finite period of time 2.5’ Clear deliverables (product, service or result) 2.5’ Process Multiple stages/series of steps 2.5’ Lead to a product/activity/resource/output 2.5’ No answer given in materials given. Most students do not give the correct answer. Project and process both should clearly produce something. Process should have multiple phases, e.g. SDLC has four phases. © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Question 10 SDLC is a time and quality trade-off. Why? The Systems Development Life Cycle Time ↑ and quality ↑ All reasonable answer is OK. No exactly correct answer. The more time you spend on a system, the higher quality the system will have. © Copyright 2011 John Wiley & Sons, Inc.

© Copyright 2011 John Wiley & Sons, Inc. Thank you! lijing@se.cuhk.edu.hk © Copyright 2011 John Wiley & Sons, Inc.

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